Microsoft . . . complained in its annual report that it was facing increasing pressure from open source companies. It claims they are stealing its ideas and benefiting from its intellectual property.
"A number of commercial firms compete with us using an open source business model by modifying and then distributing open source software to end users at nominal cost and earning revenue on complementary services and products." Also see analysis at Microsoft Watch.

So if enough users/testers are willing to do the testing for free, eventually others will end up using a finished and polished product. Problem is, users want to be just end users and get stuff done with the software, not test it

There are different levels and types of users. Some like cutting edge stuff and are willing to have an unfinished product and to report bugs.

Others are not and therefore can wait until the product is stable enough for them. It's not like they paid for the product anyway and their licence key won't expire if they upgrade to the next revision, they can pick it up whenever no restrictions.

People are still stuck on the proprietary end user mindset where you have producers and consumers. Unfortunately that is not how open source operates and the differences between the two are much more fluid.